The present invention is related generally to the art of counterbalancing systems for conventional double-hung or vertical sliding windows and the like, and more specifically to sash tethering devices which are externally mountable for universal use in connection with such counterbalancing systems.
In conventional indoor double-hung or vertical sliding windows systems, use of counterbalancing systems to ease the load of lifting the lower window sash is commonplace. Such counterbalancing systems are most commonly designed to be mounted within the window jambs such that they are substantially, if not completely, hidden from view. For this reason, conventional double-hung windows and the counterbalancing systems there for are generally custom designed and not universally interchangeable with other window brands.
While indoor double-hung windows are most commonly custom built for use with a particular counterbalancing system, outer storm windows of the double-hung type have conventionally been devoid of counterbalancing systems altogether. The reason for this is that outer storm windows are generally of light construction, not requiring any need to offset the load of the lower sash window. However, in recent times, storm windows have been built of a much more solid and heavier construction to help cut down outdoor noise levels. While conventional storm windows are generally constructed with windowpanes of {fraction (3/32)} inch thickness (SSB) or xe2x85x9 inch thickness (DSB), newer storm windows are oftentimes constructed with {fraction (3/16)} inch thickness windowpanes, or with xc2xc inch laminated glass. This is particularly the case in homes near airports and the like, where noise levels are significantly increased. Storm windows used in such areas are now commonly constructed with increased strength and insulative capacity, and consequently with increased weight.
As storm windows of this type are not commonly designed to be fitted with counterbalancing systems, particularly with those that are built into the window jambs and hidden from view, there is a distinct need for a counterbalance system which can be mounted to the exterior of such a window for universal application to any type or brand thereof. Such a universal system may be used to modify or repair existing double-hung windows, as well as be incorporated into new windows. It is with this object in mind that we have developed our improved counterbalance sash tether clasp and anchoring system as described and shown hereinafter.
In accordance with the present invention, we have conceived of an improved universally mountable sash tether clasp and anchoring device which provides for convenient accessibility and versatility in the installation and use of new or pre-existing double-hung windows. The sash tether clasp is externally mounted to the lower sash of the window, and includes an improved means for engaging the sash tethering device of the counterbalance system in readily releasable locking engagement.
The tether clasp includes a base portion which is externally mountable upon the lower window sash, and a generally U-shaped catch member and separate locking member which extend outwardly therefrom. The catch member is cantilevered at one end to the base portion and terminates at its other end in a pair of transversely spaced opposed leg members, which are defined by an open channel extending therebetween.
The locking member is disposed below the catch member and is spaced slightly therefrom. The locking member is also cantilevered at one end to the base portion and is free at its opposite end. The intermediate portion of the locking member is curved such that the extrados surface of the arcuate portion faces upwardly toward the catch member. The transverse dimensions of the locking member are less than that of the catch member, and the locking member is generally centrally disposed relative to the catch member, such that the arcuate portion thereof extends upwardly toward the channel extending between the opposite legs of the catch member.
The tethering device which connects to the tether clasp includes a typical balance cord which terminates at its free end with a generally bell-shaped anchor member. The anchor member has outer walls which diverge outwardly from its upper end toward the lower bell mouth portion thereof. The anchor member is constructed such that at least the lower bell mouth portion of the anchor member is hollow, so as to form an inwardly protruding recess in the lower end thereof.
In operation, the generally bell-shaped anchor member of the tethering device may be connected in releasable locking relation with the tether clasp by inserting the anchor member between the catch member and locking member of the tether clasp. The diverging outer wall portions of the anchor member 21 are constructed such that they may be received within the channel portion between the opposing legs of the catch member. Upon insertion of the anchor member in such manner, the lower bell mouth portion of the anchor will engage the arcuate portion of the locking member and cause the same to deflect slightly downward to allow the anchor member to move past the arc and seat against the catch member.
Once the anchor member is seated between the opposing legs of the catch member, the spring bias of the locking member will cause the same to return to its natural resting place, wherein at least the extrados surface of the arcuate portion of the locking member will extend within the lower recess portion of the bell mouth of the anchor member. By so doing, the locking member effectively holds the anchor member of the tethering device in releasable locking engagement with the catch member of the tether clasp, which is connected to the lower sash of the window. Because the counterbalance system exerts an upward biasing force on the tethering device, the outer diverging wall portions of the anchor member engage the opposing legs of the catch member, thereby effectively reducing the load of the lower window sash when opening the same.
Through the use of our universal tether clasp and anchoring system for double-hung windows, an external counterbalancing system may be used to provide versatility with respect to both installation and use on new or pre-existing windows. The improved accessibility and readily releasable locking engagement of the tether clasp and anchor system effectively enhances the performance and ease of operation of the double-hung window upon which it is installed.